If you need login device type, model and version of an iOS device, then use below code.

You'll have to import below file first then:-

 // #import `<`sys/utsname.h> 

NSString* deviceName()
{
    struct utsname systemInfo;
    uname(&systemInfo);

    return [NSString stringWithCString:systemInfo.machine
                              encoding:NSUTF8StringEncoding];
}

NSString *deviceInfo = deviceName();

Above code will return you iOS device info with following device codes and you can get yours.

@"i386"      on 32-bit Simulator
@"x86_64"    on 64-bit Simulator
@"iPod1,1"   on iPod Touch
@"iPod2,1"   on iPod Touch Second Generation
@"iPod3,1"   on iPod Touch Third Generation
@"iPod4,1"   on iPod Touch Fourth Generation
@"iPhone1,1" on iPhone
@"iPhone1,2" on iPhone 3G
@"iPhone2,1" on iPhone 3GS
@"iPad1,1"   on iPad
@"iPad2,1"   on iPad 2
@"iPad3,1"   on 3rd Generation iPad
@"iPhone3,1" on iPhone 4 (GSM)
@"iPhone3,3" on iPhone 4 (CDMA/Verizon/Sprint)
@"iPhone4,1" on iPhone 4S
@"iPhone5,1" on iPhone 5 (model A1428, AT&T/Canada)
@"iPhone5,2" on iPhone 5 (model A1429, everything else)
@"iPad3,4" on 4th Generation iPad
@"iPad2,5" on iPad Mini
@"iPhone5,3" on iPhone 5c (model A1456, A1532 | GSM)
@"iPhone5,4" on iPhone 5c (model A1507, A1516, A1526 (China), A1529 | Global)
@"iPhone6,1" on iPhone 5s (model A1433, A1533 | GSM)
@"iPhone6,2" on iPhone 5s (model A1457, A1518, A1528 (China), A1530 | Global)
@"iPad4,1" on 5th Generation iPad (iPad Air) - Wifi
@"iPad4,2" on 5th Generation iPad (iPad Air) - Cellular
@"iPad4,4" on 2nd Generation iPad Mini - Wifi
@"iPad4,5" on 2nd Generation iPad Mini - Cellular
@"iPhone7,1" on iPhone 6 Plus
@"iPhone7,2" on iPhone 6
@"iPhone8,1" on iPhone 6S
@"iPhone8,2" on iPhone 6S Plus

Hope this will help you to find out model and version of the iOS device.